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| author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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diff --git a/libstdc++-v3/doc/html/manual/profile_mode.html b/libstdc++-v3/doc/html/manual/profile_mode.html new file mode 100644 index 000000000..3c1b2d3b5 --- /dev/null +++ b/libstdc++-v3/doc/html/manual/profile_mode.html @@ -0,0 +1,146 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"><head><title>Chapter 19. Profile Mode</title><meta name="generator" content="DocBook XSL-NS Stylesheets V1.76.1"/><meta name="keywords" content=" C++ , library , profile "/><meta name="keywords" content=" ISO C++ , library "/><link rel="home" href="../spine.html" title="The GNU C++ Library"/><link rel="up" href="extensions.html" title="Part III. Extensions"/><link rel="prev" href="bk01pt03ch18s05.html" title="Testing"/><link rel="next" href="bk01pt03ch19s02.html" title="Design"/></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 19. Profile Mode</th></tr><tr><td align="left"><a accesskey="p" href="bk01pt03ch18s05.html">Prev</a> </td><th width="60%" align="center">Part III. + Extensions + +</th><td align="right"> <a accesskey="n" href="bk01pt03ch19s02.html">Next</a></td></tr></table><hr/></div><div class="chapter" title="Chapter 19. Profile Mode"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.profile_mode"/>Chapter 19. Profile Mode</h2></div></div></div><div class="toc"><p><strong>Table of Contents</strong></p><dl><dt><span class="section"><a href="profile_mode.html#manual.ext.profile_mode.intro">Intro</a></span></dt><dd><dl><dt><span class="section"><a href="profile_mode.html#manual.ext.profile_mode.using">Using the Profile Mode</a></span></dt><dt><span class="section"><a href="profile_mode.html#manual.ext.profile_mode.tuning">Tuning the Profile Mode</a></span></dt></dl></dd><dt><span class="section"><a href="bk01pt03ch19s02.html">Design</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch19s02.html#manual.ext.profile_mode.design.wrapper">Wrapper Model</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s02.html#manual.ext.profile_mode.design.instrumentation">Instrumentation</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s02.html#manual.ext.profile_mode.design.rtlib">Run Time Behavior</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s02.html#manual.ext.profile_mode.design.analysis">Analysis and Diagnostics</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s02.html#manual.ext.profile_mode.design.cost-model">Cost Model</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s02.html#manual.ext.profile_mode.design.reports">Reports</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s02.html#manual.ext.profile_mode.design.testing">Testing</a></span></dt></dl></dd><dt><span class="section"><a href="bk01pt03ch19s03.html">Extensions for Custom Containers</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s04.html">Empirical Cost Model</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s05.html">Implementation Issues</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch19s05.html#manual.ext.profile_mode.implementation.stack">Stack Traces</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s05.html#manual.ext.profile_mode.implementation.symbols">Symbolization of Instruction Addresses</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s05.html#manual.ext.profile_mode.implementation.concurrency">Concurrency</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s05.html#manual.ext.profile_mode.implementation.stdlib-in-proflib">Using the Standard Library in the Instrumentation Implementation</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s05.html#manual.ext.profile_mode.implementation.malloc-hooks">Malloc Hooks</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s05.html#manual.ext.profile_mode.implementation.construction-destruction">Construction and Destruction of Global Objects</a></span></dt></dl></dd><dt><span class="section"><a href="bk01pt03ch19s06.html">Developer Information</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch19s06.html#manual.ext.profile_mode.developer.bigpic">Big Picture</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s06.html#manual.ext.profile_mode.developer.howto">How To Add A Diagnostic</a></span></dt></dl></dd><dt><span class="section"><a href="bk01pt03ch19s07.html">Diagnostics</a></span></dt><dd><dl><dt><span class="section"><a href="bk01pt03ch19s07.html#manual.ext.profile_mode.analysis.template">Diagnostic Template</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s07.html#manual.ext.profile_mode.analysis.containers">Containers</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s07.html#manual.ext.profile_mode.analysis.algorithms">Algorithms</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s07.html#manual.ext.profile_mode.analysis.locality">Data Locality</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s07.html#manual.ext.profile_mode.analysis.mthread">Multithreaded Data Access</a></span></dt><dt><span class="section"><a href="bk01pt03ch19s07.html#manual.ext.profile_mode.analysis.statistics">Statistics</a></span></dt></dl></dd><dt><span class="bibliography"><a href="profile_mode.html#profile_mode.biblio">Bibliography</a></span></dt></dl></div><div class="section" title="Intro"><div class="titlepage"><div><div><h2 class="title"><a id="manual.ext.profile_mode.intro"/>Intro</h2></div></div></div><p> + <span class="emphasis"><em>Goal: </em></span>Give performance improvement advice based on + recognition of suboptimal usage patterns of the standard library. + </p><p> + <span class="emphasis"><em>Method: </em></span>Wrap the standard library code. Insert + calls to an instrumentation library to record the internal state of + various components at interesting entry/exit points to/from the standard + library. Process trace, recognize suboptimal patterns, give advice. + For details, see + <a class="link" href="http://dx.doi.org/10.1109/CGO.2009.36">paper presented at + CGO 2009</a>. + </p><p> + <span class="emphasis"><em>Strengths: </em></span> +</p><div class="itemizedlist"><ul class="itemizedlist"><li class="listitem"><p> + Unintrusive solution. The application code does not require any + modification. + </p></li><li class="listitem"><p> The advice is call context sensitive, thus capable of + identifying precisely interesting dynamic performance behavior. + </p></li><li class="listitem"><p> + The overhead model is pay-per-view. When you turn off a diagnostic class + at compile time, its overhead disappears. + </p></li></ul></div><p> + </p><p> + <span class="emphasis"><em>Drawbacks: </em></span> +</p><div class="itemizedlist"><ul class="itemizedlist"><li class="listitem"><p> + You must recompile the application code with custom options. + </p></li><li class="listitem"><p>You must run the application on representative input. + The advice is input dependent. + </p></li><li class="listitem"><p> + The execution time will increase, in some cases by factors. + </p></li></ul></div><p> + </p><div class="section" title="Using the Profile Mode"><div class="titlepage"><div><div><h3 class="title"><a id="manual.ext.profile_mode.using"/>Using the Profile Mode</h3></div></div></div><p> + This is the anticipated common workflow for program <code class="code">foo.cc</code>: +</p><pre class="programlisting"> +$ cat foo.cc +#include <vector> +int main() { + vector<int> v; + for (int k = 0; k < 1024; ++k) v.insert(v.begin(), k); +} + +$ g++ -D_GLIBCXX_PROFILE foo.cc +$ ./a.out +$ cat libstdcxx-profile.txt +vector-to-list: improvement = 5: call stack = 0x804842c ... + : advice = change std::vector to std::list +vector-size: improvement = 3: call stack = 0x804842c ... + : advice = change initial container size from 0 to 1024 +</pre><p> + </p><p> + Anatomy of a warning: + </p><div class="itemizedlist"><ul class="itemizedlist"><li class="listitem"><p> + Warning id. This is a short descriptive string for the class + that this warning belongs to. E.g., "vector-to-list". + </p></li><li class="listitem"><p> + Estimated improvement. This is an approximation of the benefit expected + from implementing the change suggested by the warning. It is given on + a log10 scale. Negative values mean that the alternative would actually + do worse than the current choice. + In the example above, 5 comes from the fact that the overhead of + inserting at the beginning of a vector vs. a list is around 1024 * 1024 / 2, + which is around 10e5. The improvement from setting the initial size to + 1024 is in the range of 10e3, since the overhead of dynamic resizing is + linear in this case. + </p></li><li class="listitem"><p> + Call stack. Currently, the addresses are printed without + symbol name or code location attribution. + Users are expected to postprocess the output using, for instance, addr2line. + </p></li><li class="listitem"><p> + The warning message. For some warnings, this is static text, e.g., + "change vector to list". For other warnings, such as the one above, + the message contains numeric advice, e.g., the suggested initial size + of the vector. + </p></li></ul></div><p> + </p><p>Three files are generated. <code class="code">libstdcxx-profile.txt</code> + contains human readable advice. <code class="code">libstdcxx-profile.raw</code> + contains implementation specific data about each diagnostic. + Their format is not documented. They are sufficient to generate + all the advice given in <code class="code">libstdcxx-profile.txt</code>. The advantage + of keeping this raw format is that traces from multiple executions can + be aggregated simply by concatenating the raw traces. We intend to + offer an external utility program that can issue advice from a trace. + <code class="code">libstdcxx-profile.conf.out</code> lists the actual diagnostic + parameters used. To alter parameters, edit this file and rename it to + <code class="code">libstdcxx-profile.conf</code>. + </p><p>Advice is given regardless whether the transformation is valid. + For instance, we advise changing a map to an unordered_map even if the + application semantics require that data be ordered. + We believe such warnings can help users understand the performance + behavior of their application better, which can lead to changes + at a higher abstraction level. + </p></div><div class="section" title="Tuning the Profile Mode"><div class="titlepage"><div><div><h3 class="title"><a id="manual.ext.profile_mode.tuning"/>Tuning the Profile Mode</h3></div></div></div><p>Compile time switches and environment variables (see also file + profiler.h). Unless specified otherwise, they can be set at compile time + using -D_<name> or by setting variable <name> + in the environment where the program is run, before starting execution. + </p><div class="itemizedlist"><ul class="itemizedlist"><li class="listitem"><p> + <code class="code">_GLIBCXX_PROFILE_NO_<diagnostic></code>: + disable specific diagnostics. + See section Diagnostics for possible values. + (Environment variables not supported.) + </p></li><li class="listitem"><p> + <code class="code">_GLIBCXX_PROFILE_TRACE_PATH_ROOT</code>: set an alternative root + path for the output files. + </p></li><li class="listitem"><p>_GLIBCXX_PROFILE_MAX_WARN_COUNT: set it to the maximum + number of warnings desired. The default value is 10.</p></li><li class="listitem"><p> + <code class="code">_GLIBCXX_PROFILE_MAX_STACK_DEPTH</code>: if set to 0, + the advice will + be collected and reported for the program as a whole, and not for each + call context. + This could also be used in continuous regression tests, where you + just need to know whether there is a regression or not. + The default value is 32. + </p></li><li class="listitem"><p> + <code class="code">_GLIBCXX_PROFILE_MEM_PER_DIAGNOSTIC</code>: + set a limit on how much memory to use for the accounting tables for each + diagnostic type. When this limit is reached, new events are ignored + until the memory usage decreases under the limit. Generally, this means + that newly created containers will not be instrumented until some + live containers are deleted. The default is 128 MB. + </p></li><li class="listitem"><p> + <code class="code">_GLIBCXX_PROFILE_NO_THREADS</code>: + Make the library not use threads. If thread local storage (TLS) is not + available, you will get a preprocessor error asking you to set + -D_GLIBCXX_PROFILE_NO_THREADS if your program is single-threaded. + Multithreaded execution without TLS is not supported. + (Environment variable not supported.) + </p></li><li class="listitem"><p> + <code class="code">_GLIBCXX_HAVE_EXECINFO_H</code>: + This name should be defined automatically at library configuration time. + If your library was configured without <code class="code">execinfo.h</code>, but + you have it in your include path, you can define it explicitly. Without + it, advice is collected for the program as a whole, and not for each + call context. + (Environment variable not supported.) + </p></li></ul></div><p> + </p></div></div><div class="bibliography" title="Bibliography"><div class="titlepage"><div><div><h2 class="title"><a id="profile_mode.biblio"/>Bibliography</h2></div></div></div><div class="biblioentry"><a id="id489940"/><p><span class="citetitle"><em class="citetitle"> + Perflint: A Context Sensitive Performance Advisor for C++ Programs + </em>. </span><span class="author"><span class="firstname">Lixia</span> <span class="surname">Liu</span>. </span><span class="author"><span class="firstname">Silvius</span> <span class="surname">Rus</span>. </span><span class="copyright">Copyright © 2009 . </span><span class="publisher"><span class="publishername"> + Proceedings of the 2009 International Symposium on Code Generation + and Optimization + . </span></span></p></div></div></div><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td align="left"><a accesskey="p" href="bk01pt03ch18s05.html">Prev</a> </td><td align="center"><a accesskey="u" href="extensions.html">Up</a></td><td align="right"> <a accesskey="n" href="bk01pt03ch19s02.html">Next</a></td></tr><tr><td align="left" valign="top">Testing </td><td align="center"><a accesskey="h" href="../spine.html">Home</a></td><td align="right" valign="top"> Design</td></tr></table></div></body></html> |